Enclosed circuit breaker



Dec. 15, 1959 J. N. GROVES ETAL 2,917,593

ENCLOSED CIRCUIT BREAKER Filed June 24, 1958 3 Sheets-Sheet 1 WITNESSESh ISVENTOR a Jo n roves \,r% Donald G. Portmon Dec. 15, 1959 J. N.GROVES ETAL 2,917,593

ENCLOSED cmcurr BREAKER 3 Sheets-Sheet 2 Filed June 24, 1958 I IIIIIIIJIIIIIIIIIIIIIIIY [III/111111111111!lllvjllllllllln Dec. 15, 1959J. N. GROVES ETAL 2,917,593

ENCLOSED CIRCUIT BREAKER Filed June 24, 1958 3 Sheets-Sheet 3 UnitedStates Patent ENCLOSED CIRCUIT BREAKER John N. Groves, Monaca, andDonald G. Portman, Brighton Township, Beaver County, Pa., assignors toWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania Application June 24, 1958, Serial No. 744,114

Claims. (Cl. 200-50) The invention relates to enclosed circuit breakersand more particularly to circuit breakers which are mounted insideenclosing cabinets and having an operating handle mounted on the coverof the cabinet.

An object of the invention is to provide a circuit breaker mounted in anenclosure having an openable cover with an interlock for preventingclosing of the circuit breaker when the openable cover is in the openposition.

Another object of the invention is to provide an interlocking device fornormally preventing an enclosed circuit breaker from being closed whilethe cover of the enclosure is open, but which may be manually releasedto permit closing the circuit breakerwith means for preventing manualreleasing of the interlocking device.

Another object of the invention is to provide a circuit breaker mountedin an enclosure having an openable cover with an interlocking device forpreventing closing of the circuit breaker when the cover is in the openposition, but which may be manually released to permit closing thecircuit breaker with means arranged to receive a padlock to positivelyprevent release of the interlocking device.

A further object of the invention is to provide a circuit breaker havingan insulating housing, a portion of which at one end is transparent sothat the contacts are visible, the circuit breaker being mounted in anenclosure having an openable cover'on which the operating mechanism ismounted to swing away from the breaker when the cover is opened and notblock the view of the contacts. An interlock is provided to preventclosing the breaker when the enclosure cover is open, the interlockbeing mounted at the opposite end of the breaker from the contacts so asnotto block the view of the contacts and using the same mounting holeswhich mount the interrupter.

The invention, both as to structure and operation, together withadditional objects and advantages thereof, will be best understood fromthe following detailed description thereof when read in conjunction withthe accompanying drawings.

' In said drawings:

Figure 1 is a front elevational view of a cabinet having a circuitbreaker mounted therein embodying the principles of this invention, thecabinet being shown with the cover open.

Fig. 2 is a front elevational view of the cabinet with openable coverclosed and partly broken away to more clearly show the operatingmechanism.

Fig. 3 is a front elevational view of the operating mech anism.

Fig. 4 is a vertical sectional view taken on line IVIV of Fig. 5, andlooking in the direction of the arrows.

Fig. 5 is a vertical sectional view taken on line V-V of Fig. 2 andlooking in the direction of the arrows.

Referring to the drawings, the enclosing cabinet comprises a metalcasing 11 and a cooperating metal cover 13. r The cover 13 is providedwith a rim 15 which seats against the edges of the side and end walls ofthe casing 11 in the closed position of the cover, and has a downwardlyextending edge 17 which overlaps the edges of the casing 11. The cover13 is mounted on one side wall of the casing 11 by means of a pair ofhinges 19 which permit the cover to be moved to open and closedpositions. A sealing gasket 21 supported in an annular bracket 23 isengaged by the rim 15 of the cover to exclude extraneous material fromthe interior of the cabinet which is adapted to house an electricalswitch or circuit breaker for industrial application.

A circuit breaker 25 having a pivoted handle 27 for operating thebreaker mechanism (not shown), is enclosed in the cabinet and issuitably mounted by means of mounting studs 26, 28 and 30 on brackets 26or the back wall of the casing 11. The circuit breaker 25 is preferablyof the type shown in Patent No. 2,318,298, issued May 4, 1943, to H. D.Dorfman and G. J. Freese. The circuit breaker 25 is provided withseparable contact means 24 (Fig. l) and an operating mechanism (also notshown) for opening and closing the contact means by movement of thebreaker operating handle 27. The circuit breaker described in theabove-mentioned patent is also provided with a current responsive tripdevice (not shown herein) which is operable in response to predeterminedoverload currents to effect automatic separation of the contact means.The circuit breaker is housed in an insulating housing comprising a baseand cover, the portion of the cover adjacent the contacts beingtransparent so that the contacts are visible from the front of thebreaker.

The circuit breaker 25 is adapted to be manually opened and closed bymovement of the handle 27 between an open position and a closedposition. Also, in order to reclose the contacts following an automaticopening operation, it is first necessary to reset the mechanism. This isaccomplished by movement of the handle 27 to a reset position beyond theoff position after which the handle is moved to the on position to closethe contact means. The circuit breaker mechanism and the trip device arefully disclosed in the above mentioned Patent No. 2,318,298 to whichreference may be had for the details of the construction and operationof the circuit breaker.

In order to manually operate the circuit breaker 25 when the cover 13 isclosed, an external handle 29 is rotatably mounted on the exterior ofthe cover. The handle 29 is attached to a short shaft 31 which may beintegral with the handle 29 and which is rotatably supported in anopening in the cover. Rigidly mounted on the inner end of the shaft 31for movement therewith is a cam-shaped plate forming a cam member 33.The cam member 33 is secured to the shaft 31 by means of screws 35 andcarries a pin or anti-friction roller 37 which engages in a slot 39 in asliding plate 41. The sliding plate 41 is slidably supported by groovedstuds 43 mounted on a plate 44 which is rigidly secured to the inside ofthe cover 13. An actuating member 45 is adjustably secured to the underside of the sliding plate 41 by screws 47. The actuating member 45 isprovided with a transverse opening 48 for engaging the breaker handle 27in the operative position of the handle 29in the closed position of thecover 13.

Movement of the handle 29 in clockwise direction (Fig. 3) from the on tothe off position rotates the cam member 33 in the same direction andthis movement, acting through the pin and slot connection 37-39, slidesthe plate 41 downwardly (Fig. 3) and toward the right as seen in Fig. 4.Due to the engagement of the actuating member 45 with the breaker handle27 this movement moves the latter clockwise from the on to the offposition to effect opening of the breaker contacts.

Movement of the handle 29 in a counterclockwise direction from the oif"to the 'cn'position reverses the direction of movement of the parts justdescribed and moves the plate 41 upwardly (Fig. 3) and toward the left(Fig. 4) to the on position. This movement through the engagement of theactuating member 45 with the breaker handle 27 moves the breaker handlecounterclockwise (Fig. 4) to the on position to close the breakercontacts.

Locking means is provided for locking the cover 13 to prevent openingthereof. The locking means is effective to lock the cover closed in allpositions of the operating handle 29 except when the handle is movedbeyond the off position to a reset position in which position of thehandle the .cover may be opened. The locking means comprises a lockingmember 49 pivotally mounted by means of a screw 51 rigidly secured tothe locking member for movement therewith. The screw 51 extends throughopenings in the plate 44 and in the cover 13 which openings formbearings for the screw. The locking member 49 is disposed between thecam member 33 and the plate 44 and is retained in place by the cammember. A clearance opening 53 (Fig. 2) is provided in the lockingmember 49 to permit movement thereof relative to the shaft 31. Thelocking member 49 is pro-vided with a downwardly extending latchingportion 55 (Figs. 4 and which is adapted to engage in a notch 57 of abracket 59 rigidly secured to the bottom of the casing 11 and extendingupwardly therefrom. The locking member is biased to locking position bya spring 61 coiled about a pin 63 mounted on the plate 44.

The cam member 33 is provided with a shoulder 65 which is adapted toengage the locking member 49, when the handle 29 is moved beyond the offposition, and move the locking member to the unlocking position. It willbe seen that it is necessary to move the handle 29 beyond the offposition before the cover 13 may be opened. This insures that thecircuit breaker .25 is operated to the off or open contact positionbefore the cover can be opened.

When the cover 13 is opened the actuating member 45 separates from thebreaker handle 27 and, upon release of the handle 29, the plate 41together with the actuating member 45 is returned to the on position bymeans of a spring 67 which is connected under tension between thesliding plate 4-1 and the fixed plate 44 so as to bias the plate 41upwardly (Fig. 2) and toward the left (Fig. 4) or toward the onposition. Movement of the plate 41 to the on positionby the spring 67,due to the pin or slot connection 3739 rotates the cam member 33 and thehandle 29 back to the on position thereby serving as a warning shouldthe cover 13 be closed with the handle 29 in a position different fromthe breaker handle 2-7. Thus the handle 29 never indicated off when thebreaker is in the closed position.

When the cover 13 is closed and the handle 29 is moved back to the onposition closing the circuit breaker,-the cam member 33 releases thelocking member 49 which is returned to the locking position by thespring 61.

Interlocking means is provided that is operable upon opening of thecover 13 to engage and prevent movement of the handle 27 of the circuitbreaker to close the breaker contacts. The interlocking means comprisesa pivoted interlocking member 71 (Figs. 1 and 2) mounted on the circuitbreaker 25 and a cam 73 rigidly secured to the cover 13.

The circuit breaker 25 is provided with a molded insulating housingcomprising a base portion 75 and a cover portion 77, the base portion 75extend endwise beyond the cover portion forming a ledge 79 at each endof the housing. The cover portion 77 is provided with a transparentplate 80 over the area adjacent the contacts 24 so that the contacts arevisible from the front of the breaker. The mounting studs 28 and 30 areelongated and extend upwardly to a point above the top of the cover 77as seen in Figs. 4 and 5. The upper ends of the mounting studs 28 and 30are enlarged as at 81 and an angular plate 83 is mounted thereon and isrigidly secured to the stud 28 by a nut 85. Spacers 87 are disposedbetween the enlarged portions 31 of the studs 28 and 30 and are seatedin counter bores in the base portion 75 of the breaker housing. Theinterlocking plate 71 is pivotally supported on the upper end of themounting stud 30 at the end of the breaker opposite the contacts and isheld in place by a nut 89 threaded on the upper end of the stud 30. Theinterlocking member 71 is biased by means of a spring 91 in a counterclockwise direction from the portion shown in Fig. 2 to the lockingposition as shown in Fig. 1. In the closed position of the cover 13, thecam 73 on the cover engages a tail 93 on the locking member 71 and holdsit in the unlocking position which permits free operation of the breakerby the external handle 29 with the cover 13 closed.

When the cover 13 is opened the cam 73 is disengaged from the tail 93 ofthe locking member 71 whereupon the spring 91 moves the locking memberfrom the position shown in Fig. 2 to the locking position (Fig. 1) inwhich a hook-shaped locking portion 95 is in the path of closingmovement of the breaker handle 27 thus preventing movement of thebreaker handle to the on position while the cover 13 is open. When thecover 13 is closed the cam 73 engages the tail 93 and moves the lockingmember 71 to the unlockingposition where it is held until the cover 13is again opened.

It will be noted that the locking plate 71 in the locking position (Fig.1), which it assumes when the cover 13 is open, does not extend over thetransparent plate and, therefore, does not block theview of the contacts24.

The interlock provided by the member 71 as seen in Fig. 1 can bedefeated by manually moving the member 71 out of the path of the breakerhandle 27 which can then be moved to the on position. This could resultin a hazardous condition for a person working on the circuit controlledby the circuit breaker. In order to prevent deliberate defeat of theinterlock, means is provided for locking the member 71 in its lockingposition as shown in Fig. 1. This means comprises a slot 97 in the fixedplate 83 and a corresponding slot 99 in the locking member 71. As seenin Fig. 2, when the cover 13 is closed and the locking member 71 is inits retracted position the slots 9799 are out of line. Upon opening thecover the locking member 71 is moved to locking position (Fig. 1)bringing the slots 9799 into alignment so that the shackle of a padlock101 may be inserted through both of the slots thereby rigidly holdingthe locking member 71 in locking position and preventing defeat of theinterlock.

The invention provides an improved interlocking device for preventingaccidental closing of an enclosed circuit breaker when the cover of theenclosure is open and also provides means for positively preventingdeliberate defeat of the interlocking device.

Having described the invention in accordance with the provisions of thepatent statutes, it is to be understood that various changes andmodifications may be made in the structural details thereof withoutdeparting from the spirit of the invention.

We claim as our invention:

1. An enclosed circuit breaker having an operating handle movable tooperate said circuit breaker, a casing in which said circuit breaker ismounted having an openable cover, operating means mounted on said coverand having means thereon for engaging and moving said operating handle,a biased member movable in a plane substantially parallel to the base ofsaid casing to engage said operating handle to prevent closing saidcircuit breaker when the cover is moved to its open position, saidbiased member being actuated by movement of said cover to the closedposition to permit closing the circuit breaker when the cover is closed.

2. An enclosed circuit breaker having an operating handle movable tooperate said circuit breaker, a casing in which said circuit breaker ismounted including an openable cover, operating means mounted on saidopenable cover having means thereon for engaging and moving saidoperating handle, a biased member movable in a plane substantiallyparallel to the base of said circuit breaker upon opening of said coverto engage said operating handle and prevent closing said circuit breakerwhen the cover is moved to its open position, and means on said coverengaging and actuating said member when said cover is moved to theclosed position to permit closing said circuit breaker when the cover isclosed.

3. An enclosed circuit breaker having an operating handle movable tooperate said circuit breaker, a casing in which said circuit breaker ismounted including an openable cover, operating means mounted on saidcover having means thereon engaging and moving said operating handle toopen and close said circuit breaker, a biased interlocking membermovable upon opening said cover to engage said operating handle andprevent closing said circuit breaker when said cover is open, saidinterlocking member being manually releasable to permit closing saidcircuit breaker when said cover is open, and means for receiving apadlock to prevent manual release of said interlocking member.

4. An enclosed circuit breaker having an operating handle movable tooperate said circuit breaker to open and closed positions, a casing inwhich said circuit breaker is mounted including an openable cover, anoperating mechanism mounted on said openable cover having means thereonfor engaging and moving said operating handle, a locking member normallylocking said cover closed in the position of said operating mechanism inwhich said circuit breaker is closed, said operating mechanism movingsaid locking member to unlocking position to permit opening said coverwhen said operating mechanism is moved to a position in which saidcircuit breaker is open, an interlocking member movable in a planesubstantially parallel to the base of said casing to engage saidoperating handle to prevent closing of said circuit breaker when saidcover is moved to open position, and means on said cover engaging andmoving said interlocking member to unlocking position by movement ofsaid cover to closed position.

- 5. An enclosed circuit breaker having an operating handle movable tooperate said circuit breaker to open and closed positions, a casing inwhich said circuit breaker is mounted including an openable cover, anoperating mechanism mounted on said openable cover having means thereonfor engaging and moving said operating handle, a locking member normallylocking said cover closed in the position of said operating mechanism inwhich said circuit breaker is closed, said operating mechanism movingsaid locking member to unlocking position to permit opening said coverwhen said operating mechanism is moved to a position in which saidcircuit breaker is open, an interlocking member movable to engage saidoperating handle to prevent opening of said circuit breaker when saidcover is moved to open position, said interlocking member being manuallyreleasable to permit closing said circuit breaker while said cover isopen, means for receiving a padlock to prevent manual release of saidbiased member, and means on said cover engaging and moving saidinterlocking member to unlocking position by movement of said cover toclosed position.

6. An enclosed circuit breaker having an operating handle movable toopen and close said circuit breaker, a casing in which said circuitbreaker is mounted including an openable cover, operating mechanismmounted on said openable cover and having means thereon for engaging andmoving said operating handle, mounting means 6 mounting said circuitbreaker in said casing, an interlocking member pivotally supported onsaid mounting means and movable in a plane substantially parallel to thebase of said circuit breaker to engage said operating handle to preventclosing said circuit breaker when said cover is moved to the openposition.

7. An enclosed circuit breaker having an operating handle movable toopen and close said circuit breaker, a casing in which said circuitbreaker is mounted includ ing an openable cover, operating mechanismmounted on said openable cover and having means thereon for engaging andmoving said operating handle, mounting means mounting said circuitbreaker in said casing, an interlocking member pivotally supported onsaid mounting means and movable in a plane substantially parallel to thebase of said casing to engage said operating handle to prevent closingsaid circuit breaker when said cover is moved to the open position, anda cam member mounted on said cover and disposed to engage and move saidinterlocking member to unlocking position when said cover is moved tothe closed position.

8. An enclosed circuit breaker having an operating handle movable toopen and close said circuit breaker, a casing in which said circuitbreaker is mounted including an openable cover, operating mechanismmounted on said openable cover and having means thereon for engaging andmoving said operating handle, mounting means mounting said circuitbreaker in said casing, an interlocking member pivotally supported onsaid mounting means and movable to engage said operating handle toprevent closing said circuit breaker when said cover is moved to theopen position, and a means comprising a member fixedly mounted on saidmounting means and adapted to receive a padlock to prevent movement ofsaid interlocking member to unlocking position.

9. An enclosed circuit breaker having visible contact means at one endof the breaker and an operating handle movable to open and close saidcontact means, a casing in which said circuit breaker is mountedincluding an openable cover, operating mechanism mounted on saidopenable cover to be moved away from said breaker upon opening of saidcover, means on said operating mechanism engaging said handle when saidcover is closed to operate said contact means, an interlocking membermovable upon opening said cover to engage said operating handle andprevent closing said contact means when said cover is open, saidinterlocking member being mounted adjacent the end of said breakeropposite said visible contact means.

10. A circuit breaker having a two-part housing of molded insulatingmaterial comprising a base portion and a cover portion, separablecontact means disposed in said housing, an operating handle movable toopen and close said contact means, said cover portion adjacent saidcontact means being transparent so that said contact means are visiblefrom the front of the breaker, a casing in which said circuit breaker ismounted including an openable cover, operating mechanism mounted on saidopenable cover having means for engaging and moving said operatinghandle, said operating mechanism being moved away from said circuitbreaker upon opening of said openable cover, an interlocking membermounted at the end of said breaker opposite said contacts and movableupon opening of said openable cover to engage said operating handle andprevent movement of said handle to close said contacts when said coveris open.

References Cited in the file of this patent UNITED STATES PATENTS2,512,505 Rowe June 20, 1950 2,695,934 Wills Nov. 30, 1954 2,813,162Wallace et a1. Nov. 12, 1957 2,832,860 Matthias Apr. 29, 1958

